Lichen

Lichen is a compound organism, made up of two species. A fungus and a cyanobacteria or green algae live symbiotically, and both are benefited from this mutualistic relationship. In exchange for a safe habitat to live in, the cyanobacteria or green algae provide food to the fungus from their photosynthetic processes. (1) The body of a lichen is a thallus, or a plant body that is not differentiated into stems and leaves, and lacks roots and a vascular system.

Pioneer Species

Lichen are considered pioneer species, or the first organism to appear in areas of primary succession. (2) They are able to colonize bare rocks, and an ecosystem is then able to begin developing on them.